Elongate tubular devices, such as diagnostic or treatment catheters or sheaths may be provided for introduction into a patient's body, e.g., the patient's vasculature or other body lumens. For example, a catheter may have a distal portion configured to be introduced into a body lumen and advanced to one or more desired locations within the patient's body by manipulating a proximal end of the catheter.
To facilitate introduction of such a catheter, one or more wires, cables, or other steering elements may be provided within the catheter, e.g., that are coupled to the distal portion and may be pulled or advanced from the proximal end to deflect the distal portion. For example, a steering element may be provided that is intended to deflect the distal portion within a predetermined plane and/or into a desired curved shape.
Pull wires are a common way to impart deflection ability to such a catheter. However, there are a number of drawbacks associated with such pull wires. For example, a pull wire occupies a significant amount of space within the catheter body. In addition, a pull wire frequently needs to be reinforced, e.g., on the inside and outside of the braid or other reinforcement of the catheter, e.g., to prevent “pull through” when the pull wire is actuated by pushing or pulling, i.e., the resulting bending moment may cause the pull wire to separate layers of or tear at least partially through the wall of catheter, potentially splitting the catheter. Further, a pull wire can make the torque properties of the catheter non-homogenous, making it difficult or impossible to torque the catheter when the pull wire is actuated, e.g., within a tortuous pathway. Further, auxiliary lumens, in particular those located in the wall of a large bore sheath, are difficult to manufacture with consistency due to difficulties with alignment, hand assembly, and the like.
For many applications, such a catheter may include one or more electrodes and/or sensing elements coupled to one or more wires or other conducting elements that extend along at least a portion of the catheter. These components, however, may increase the overall size of the catheter, e.g., to provide a lumen for the wires, given the need for other lumens in the device, e.g., a primary lumen, pull wire lumen(s), and the like. Further, the material of the wire(s) may not easily accommodate bending of the catheter, e.g., when a pull wire is used to steer the catheter during delivery and/or otherwise during a procedure, and/or the wire(s) may modify the deflection profile of the catheter adversely.
Accordingly, there is a need for improved steerable catheters, sheaths, and other tubular devices and methods of their manufacture.